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authorMartin K. Petersen <martin.petersen@oracle.com>2017-04-04 10:42:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-21 09:30:05 +0200
commitb689dfbed8c8432a18c73fc261c030d8b3e24e00 (patch)
tree476917c1f8d340870dc9fa2c3fe0607a44b935e3
parent448961955592c46f1490fb6ca8d3e52ce17e6222 (diff)
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scsi: sd: Fix capacity calculation with 32-bit sector_t
commit 7c856152cb92f8eee2df29ef325a1b1f43161aff upstream. We previously made sure that the reported disk capacity was less than 0xffffffff blocks when the kernel was not compiled with large sector_t support (CONFIG_LBDAF). However, this check assumed that the capacity was reported in units of 512 bytes. Add a sanity check function to ensure that we only enable disks if the entire reported capacity can be expressed in terms of sector_t. Reported-by: Steve Magnani <steve.magnani@digidescorp.com> Cc: Bart Van Assche <Bart.VanAssche@sandisk.com> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/scsi/sd.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d2877d713b62..4d5207dff960 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2051,6 +2051,22 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
#define READ_CAPACITY_RETRIES_ON_RESET 10
+/*
+ * Ensure that we don't overflow sector_t when CONFIG_LBDAF is not set
+ * and the reported logical block size is bigger than 512 bytes. Note
+ * that last_sector is a u64 and therefore logical_to_sectors() is not
+ * applicable.
+ */
+static bool sd_addressable_capacity(u64 lba, unsigned int sector_size)
+{
+ u64 last_sector = (lba + 1ULL) << (ilog2(sector_size) - 9);
+
+ if (sizeof(sector_t) == 4 && last_sector > U32_MAX)
+ return false;
+
+ return true;
+}
+
static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
unsigned char *buffer)
{
@@ -2116,7 +2132,7 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
return -ENODEV;
}
- if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
+ if (!sd_addressable_capacity(lba, sector_size)) {
sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
"kernel compiled with support for large block "
"devices.\n");
@@ -2202,7 +2218,7 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
return sector_size;
}
- if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
+ if (!sd_addressable_capacity(lba, sector_size)) {
sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
"kernel compiled with support for large block "
"devices.\n");